A rack generally includes a rack/chassis management controller (RMC/CMC), at least a rack backplane (RBP), at least a tray backplane (TBP), at least a node, a fan board (FB), and a power distribution board (PDB). Each rack backplane is connected to at least one tray backplane. Each tray backplane is connected to at least one node. Each node is a server node and includes a baseboard management controller (BMC). The fan board is connected to at least a fan. The power distribution board includes at least a power supply unit (PSU).
Referring to FIG. 1, a rack depicted therein includes an RMC/CMC 9, an RPB 91, two TBPs 93, 94, five nodes 931, 932, 941, 942, 943 respectively having five BMCs 933, 934, 944, 945, 946, an FB 95, three fans 951, 952, 953, a PDB 92, and three PSUs 921, 922, 923. The BMCs 933, 934 are electrically connected to the RMC/CMC 9 via the TBP 93 and the RBP 91. The BMCs 944, 945, 946 are electrically connected to the RMC/CMC 9 via the TBP 94 and the RBP 91. The three fans 951, 952, 953 are electrically connected to the BMCs 933, 934 via the FB 95, the RBP 91, and the TBP 93, and are electrically connected to the BMCs 944, 945, 946 via the FB 95, the RBP 91, and the TBP 94. The BMCs 933, 934, 944, 945, 946 are configured to monitor operation parameters associated with corresponding fans 951, 952, 953, for example, temperature and speed of rotation of each corresponding fan 951, 952, 953. The RMC/CMC 9 is configured to receive the operation parameters of the fans 951, 952, 953 from the BMCs 933, 934, 944, 945, 946, and to control, e.g., the speed of rotation of the fans 951, 952, 953 according to the operation parameters in order to adjust the temperature inside the rack. However, to have adequate communication interface and sensing interface, and sufficient computation ability for the RMC/CMC 9 requires a higher level control chip, so the cost is high. For lowering the cost, plenty of research and development in the relevant field has been performed in an attempt to use one of the BMCs to play the role of the CMC. One attempt wishes to make use of “handshaking” in deciding which of the BMCs is to take over the role of the CMC. However, due to complexity in hardware design and corresponding software implementation involved in realizing handshaking, such as not been successfully realized to date.